ASTM F1805-99

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
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Designation: F 1805 – 99
Standard Test Method for
Single Wheel Driving Traction in a Straight Line
on Snow- and Ice-Covered Surfaces
This standard is issued under the fixed designation F 1805; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope F 538 Terminology Relating to the Characteristics and Per-
formance of Tires
1.1 This test method covers a procedure for measuring the
F 1046 Guide for Preparing Artificially Worn Passenger and
driving traction of passenger car and light truck tires while
Light Truck Tires for Testing
traveling in a straight line on snow- or ice-covered surfaces.
F 1572 Test Methods for Tire Performance Testing on Snow
1.2 This test method utilizes a dedicated, instrumented,
and Ice Surfaces
four-wheel rear-wheel drive test vehicle with a specially
F 1650 Practice for Evaluating Tire Traction Performance
instrumented drive axle to measure fore-aft and vertical forces
Data Under Varying Test Conditions
acting on a single driven test tire.
1.3 This test method is suitable for research and develop-
3. Terminology
ment purposes where tires are compared during a single series
3.1 Definitions:
of tests. They may not be suitable for regulatory statutes or
3.1.1 test (or testing), n—a procedure performed on an
specification acceptance because the values obtained may not
object (or set of nominally identical objects) using specified
necessarily agree or correlate either in rank order or absolute
equipment that produces data unique to the object (or set).
traction performance level with those obtained under other
F 538
environmental conditions on other surfaces or the same surface
3.1.1.1 Discussion—Test data are used to evaluate or model
after additional use.
selected properties or characteristics of the object (or set of
1.4 The values stated in SI units are to be regarded as the
objects). The scope of testing depends on the decisions to be
standard. The values given in parentheses are for information
made for any program, and sampling and replication plans (see
only.
definitions below) need to be specified for a complete program
1.5 This standard does not purport to address all of the
description.
safety concerns, if any, associated with its use. It is the
3.1.2 test run, n—a single pass of a loaded tire over a given
responsibility of the user of this standard to establish appro-
test surface. F 538
priate safety and health practices and determine the applica-
3.1.3 traction test, n— in tire testing, a series of n test runs
bility of regulatory limitations prior to use.
at a selected operational condition; a traction test is character-
2. Referenced Documents ized by an average value for the measured performance
parameter. F 538
2.1 ASTM Standards:
3.1.4 test tire, n—a tire used in a test. F 538
E 274 Test Method for Skid Resistance of Paved Surfaces
3.1.5 test tire set, n—one or more test tires, as required by
Using a Full-Scale Tire
the test equipment or procedure, to perform a test, thereby
E 1136 Specification for a Radial Standard Reference Test
producing a single test result. F 538
Tire
3.1.5.1 Discussion—The four nominally identical tires re-
F 424 Test Method for Tires for Wet Driving Traction in
quired for vehicle stopping distance testing constitute a test tire
Straight-Ahead Motion Using Highway Vehicles
set. In the discussion below where the test tire is mentioned, it
F 377 Practice for Calibration of Braking/Tractive Measur-
is assumed that the test tire set may be substituted for the test
ing Devices for Testing Tires
tire, if a test tire set is required for the testing.
F 457 Test Method for Speed and Distance Calibration of a
3.1.6 candidate tire, n—a test tire that is part of a test
Fifth Wheel Equipped with Either Analog or Digital
3 program. F 538
Instrumentation
3.1.6.1 Discussion—The term “candidate object” may be
used in the same sense as candidate tire.
This test method is under the jurisdiction of Committee F-9 on Tires and is the
3.1.7 test matrix, n— in tire testing a group of candidate
direct responsibility of Subcommittee F09.20 on Vehicular Testing.
tires, usually with specified reference tires; all tests are
Current edition approved Sept. 10, 1999. Published November 1999. Last
previous edition F 1805 – 98. Originally published as F 1805 – 98.
normally conducted in one testing program. F 538
Annual Book of ASTM Standards, Vol 04.03.
3.1.8 reference tire, n—a special tire included in a test
Annual Book of ASTM Standards, Vol 09.02.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
F 1805
program; the test results for this tire have significance as a base range. The recommended vehicle test speed is 8.0 km/hr (5.0
value or internal benchmark. F 538 mph).
3.1.9 control tire, n—a reference tire used in a specified
5. Significance and Use
manner throughout a test program. F 538
5.1 This test method describes a technique for assessing the
3.1.9.1 Discussion—A control tire may be of either type and
performance characteristics of tires in a winter environment on
typical tire use is the reference (control) tire in Practice F 1650
snow and ice surfaces. When snow is referred to hereafter, ice
that provides algoritms for correcting (adjusting) test data for
is implied as appropriate.
bias trend variations (See Practice F 1650 and Annex X1).
5.2 The measured values quantify the dynamic longitudinal
3.1.10 surface monitoring tire, n—a reference tire used to
traction properties of tires under driving torque. Dynamic
evaluate changes in the test surface over a selected time period.
traction properties are obtained on snow surfaces prepared in
F 538
accordance with the stated test procedures and attempts to
3.1.11 standard reference test tire (SRTT), n—a tire that
quantify the tires’ performance when integrated into a vehicle-
meets the requirements of Specification E 1136, commonly
environmental system. Changing any one of these environmen-
used as a control tire or a surface monitoring tire. F 538
tal factors will change the measurements obtained on a
3.1.12 vertical load, n—the normal reaction of the tire on
subsequent test run.
the road which is equal to the negative of normal force.
5.3 This test method addresses longitudinal driving traction
F 538
properties only on snow and ice surfaces. Refer to Test
3.1.13 spin velocity, n—the angular velocity of the wheel
Methods F 1572 for test methods for braking and lateral
about its spin axis. F 538
traction properties on snow or ice, or both. Refer to Test
3.1.14 longitudinal slip velocity (L/T), n— the effective
Method F 424 for longitudinal driving traction testing utilizing
rolling radius multiplied by the difference between the spin
the two-vehicle dynamometer method.
velocity (in rad/unit time) of a driven or braked tire and that of
a free rolling tire when each is traveling in a straight line. 6. Interferences
F 538
6.1 Factors that may affect tire snow performance and must
3.1.15 longitudinal force (F), n— of a tire, the component
be considered in the final analysis of data include:
of the tire force vector in the X8 direction. F 538
6.1.1 Snow temperature.
3.1.16 driving force (F), n— of a tire, the positive longitu-
6.1.2 Ambient temperature,
dinal force resulting from the application of driving torque.
6.1.3 Mechanical breakdown of the agglomerated snow-
F 538
flake into granular crystals,
3.1.17 driving coeffıcient (nd), n—the ratio of the driving
6.1.4 Solar load,
force to a normal force. F 538
6.1.5 Tire temperature,
3.1.18 snow, soft pack, n— in tire testing, freshly fallen or
6.1.6 Tire wear condition (preparation),
deeply groomed base snow with 5.0 to 7.5 cm (2 to 3 in.) loose
6.1.7 Tire pressure,
snow. F 538
6.1.8 Tire vertical load,
3.1.19 snow, medium pack, n— in tire testing, groomed
6.1.9 Snow surface characteristics, and
packed base with 2.5 to 5.0 cm (1 to 2 in.) loose snow.
6.1.10 Rim selection.
F 538
7. Apparatus
3.1.20 snow, medium hard pack, n— in tire testing, packed
7.1 The test vehicle shall have the capability of maintaining
base with some loose snow. F 538
the specified test speed 6 0.8 km/hr (6 0.5 mph) during all
3.1.21 snow, hard pack, n— in tire testing, packed base
levels of driving torque application.
without loose snow. (See Annex A2 for additional informa-
7.2 The test vehicle shall be equipped with an automatic
tion.) F 538
throttle actuator to allow the gradual increase of driving torque
3.1.22 ice, dry, n—smooth ice without loose surface mate-
at a predetermined (repeatable) rate.
rials. (See Annex A2 for additional information.) F 538
7.3 The test vehicle shall be a rear drive, four wheel
3.1.23 grooming, v—in tire testing, mechanically reworking
passenger car or a light truck under 4536 kg (10 000 lbs) GVW.
a snow test surface in order to obtain a surface with more
The range of test tires and load conditions will determine the
consistent properties. F 538
vehicle size and selection. Utilizing a front wheel drive test
4. Summary of Test Method
vehicle is not addressed in this standard although the basic
4.1 These test methods describe the use of an instrumented procedures could be applied with appropriate conditional
modifications.
vehicle with a single test wheel capable of measuring the tire
performance properties under drive torque on snow and ice 7.4 The test vehicle shall be instrumented to measure
surfaces when traveling in a straight line. longitudinal and vertical forces at the tire and test surface
4.2 The test is conducted by driving the test vehicle over the interface during the application of driving torque.
test surface. Driving torque is gradually increased to the test 7.5 The test vehicle shall have provisions to automatically
wheel while maintaining the vehicle speed by applying braking and completely disengage the brake on the test wheel (if
torque to the non-test wheels of the vehicle. The driving installed) prior to throttle application. Complete disengage-
traction coefficient is determined from the measured values of ment is necessary to eliminate all drag that might be caused by
longitudinal and vertical forces over a specified slip or time the brake assembly.
F 1805
7.6 The tire installed opposite the instrumented test wheel driving torque application. The transducer shall have the same
shall have a traction coefficient at least 50 % greater than any specifications as those described in 7.8.4
anticipated test tire. A tire chain may be utilized when testing
7.8.6 Signal Conditioning and Recording System—All sig-
on snow surfaces. The tire shall be selected to have an outside nal conditioning and recording equipment shall provide lenear
diameter that is within6 2.5 cm (6 1 in.) of that of the test tire.
output with necessary gain and date reading resolution to meet
the requirements of 7.8.1. Additionally, it shall have the
7.7 A suitable ride height adjustment system on the rear axle
shall be provided to permit adjustment for each tire size and following specifications:
7.8.6.1 Minimum Frequency Response—flat from dc to 30
load to minimize transducer crosstalk as established during
calibration. Hz, within 61%,
7.8.6.2 Tire vertical load, longitudinal force, vehicle and
7.8 Instrumentation— The test wheel position on the test
wheel speeds and a time base must be recorded in phase (0 to
vehicle shall be equipped with a wheel rotational velocity
30 Hz 65°),
measuring system and with transducers to measure the dy-
7.8.6.3 Signal-to-Noise Ratio—at least 20/1,
namic longitudinal force and vertical load at the test wheel.
7.8.6.4 Gain shall be sufficient to permit full-scale display
7.8.1 General Requirements for Measurement System—The
for full-scale input signal level,
instrumentation system shall conform to the following overall
7.8.6.5 Input impedance shall be at least ten times larger
requirements at ambient temperatures between –23 and 43°C
than the output impedance of the signal source,
(–10 and 110°F):
7.8.6.6 The system must be insensitive to vibrations, accel-
7.8.1.1 Overall system accuracy, force—6 1.5 % of vertical
eration, and changes in ambient temperature. The error in
load or traction force from 450 N (100 lbf) to full scale.
reading shall not exceed 1 % full scale when subjected to
7.8.1.2 Overall system accuracy, speed—6 1.5 % of speed
vibration acceleration of 49.0 m/s (5 g’s) in the 0.5 to 40 Hz
from 6.4 km/h (4.0 mph) to 64.0 km/h (40.0 mph).
frequency range and operating temperature range from –23 to
7.8.1.3 Shunt Calibration—All strain-gage transducers shall
43°C (–10 to 110°F),
be equipped with shunt calibration resistors that can be
7.8.6.7 The system shall not be affected by storage tempera-
connected before or after test runs. The calibration signal shall
ture variations between –40 and 71°C (–40 and 160°F),
be in the range of the expected measurement for each analogue
7.8.6.8 The individual analog inputs shall have a sample
channel.
rate of not less than 100 samples/second,
7.8.1.4 Ruggedness—The exposed portions of the system
7.8.7 Power Supply— The power supply for transducers and
shall tolerate 100 % relative humidity (rain or spray) and all
recording system shall meet or exceed requirements specified
other adverse conditions such as dust, shock, and vibrations
by transducer and recorder manufacturers.
which may be encountered in regular operation.
7.8.8 Mercury thermometers or electronic measurement de-
7.8.2 Vehicle Speed— Vehicle forward speed (normally
vices for taking surface and ambient temperatures shall have a
obtained from a front non-driven wheel on the test vehicle)
resolution of 0.5°C (1°F) and an accuracy of 6 1°C (+ 2°F).
shall be measured digitally with an encoder or optical system
having a minimum of 500 counts per revolution. Output shall
8. Calibration
be directly visible to the driver and shall be simultaneously
8.1 All instrumentation shall be calibrated within six
recorded. It may be necessary on a very low coefficient surface,
months prior to testing.
i.e., ice, to disconnect any braking action to the wheel being
8.2 Calibrate the reference loadcell by inputting known
utilized for measuring vehicle speed.
vertical and horizontal forces. The known forces must be
7.8.3 Test Wheel Speed— Test wheel speed shall be mea-
traceable to the National Institute of Standards and Technology
sured digitally with an encoder or optical system having a
(NIST).
minimum of 1000 counts per revolution. The output shall be
8.3 Calibrate the transducer for measuring
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